Core drill



March 6, 1928. 1,661,426

c. J. HILLMAN CORE DRILL Filed April 29. 1926 Ijgl.

ATTQENEY 1 I E v KyvTo e Patented Mar. 6, 1928.

UNITED STATES CARL J. HILLMA'N, F HOUSTON, TEXAS.

CORE DRILL.

Application filed April 29, 1926. Serial No. 105,347.

My invention relates to the art of. taking cores during the operation of drilling oil wells, being more particularly a core drill of the reciprocatory type.

The taking of cores during the drilling operations for oil wells has generally been accomplished by core drills of the rotary type, and so far as I have been able to discover no core drill of the reciprocatory type has been successfully used, although a considerable demand for such type of drill has been present in the oil fields for a long time.

The principal object of my invention is to produce a core drill of the class described, that is of the reciprocatory type, of simple form and construction, which may be operated on the string of tools ordinarily used in the standard drilling operation;

Other objects and advantages will appear hereinafter from the following description.

Referring to the drawings which are for illustrative purposes only,

Fig. 1 is a vertical sectional view of a core drill embodying a form of my invention.

Fig. 2 is a sectional View on line X Fig. 1.

a Fig. 3 is a side elevation of the lower end of the drill shown in Fig. 1, and

Fig. 4 is an inverted plan'view of the lower end-of the drill shown in Fig. 3.

11 designates the drill body having a longitudinal, central opening 12 formed therein, the lower end of such opening terminating in an enlarged threaded recess 13, which is adapted to receive the threaded upper end 14 of a cutter head 15, such cutter head having a circular shoulder 16, which abuts against the lower end of the body 11. The head 15 is provided with a central opening 17, in alignment with the opening 12 in the drill body, and is further provided with cutting edges or blades 18, extending.v radially in other on each side of the opening 17. It is to be understood that the character of the cutting edges 18 just referred to, may be varied without departing from the spirit of my invention.

20 designates a core-receiving tube, mountedto move freely within the central opening 12 of the body 11, the lower end of such tube 20 terminating in a circular cutter 21, and being provided near its lower end on the inside thereof with c re-retainin alignment with each" members 22, which, in the present form, contheirlower ends in any suitable manner to the inside of the tube 20. This tube is interiorly threaded at its upper end to receive a plug 24, through which extends laterally a pin 25, the ends of such pin extending into slots 26, formed in the body 11 and extending longitudinally therein, as clearly shown. in Fig. 1 of the drawing.

The tube 20 is provided near its upper end with a series of perforations 28, through which mud or other material in the tube 20 is discharged as the core enters such tube and passes upwardly therein. Threaded into the upper end of the plug 24 is a stud 30, having a washer 31 thereon, limited in its upward movement by means of a pin 32. Between the washer 31 and the plug 21 is a coiled suring 33 which has a tendency to elastically retain the washer 31 against the pin 32, the washer, however, being adapted to be engaged by a shoulder 34 formed on the inner walls of the opening 12 in the body 11, such opening 12 terminating in a recess 35 adapted to receive the upper end of the stud 30 during certain operations of the drill.

The upper end of the body 11 terminates in a threaded pin 36, arranged to be received by the threaded lower end of the ordinary rods used in standard drilling operations.

The drill operates in the following manner: Assuming that the drill is on the bottom of the hole and the parts in the position shown in 1, as the tools are raised the body 11 is raised, the tube 20, however,

remaining on the bottom of the hole, or approximately so. As the tools descend the body 11 moves downwardly and the cutters 18 strike the bottom of the hole 'performing their function of cutting such hole. The impact of the tool striking the washer 31' through the meduim of the shoulder 34 of the body also drives the core tube 20 ahead, which by virtue of the teeth 21 thereon, engages the formation and cuts the core.

As is well known, during the reciprocation of the tools in the standard drill operation, the tools are rotated intermittently and the rotation of thebody 11 is imparted also to the core tube 20, due to the engagement of the pin 25 against the walls of the slots 26, in the body 11. As the operation just described is repeated, and the drill moves forward as indicated in dotted lin s in Fig. 1,

the core formed by the cutter 21 enters the core tube 20, and is retained therein by means of the core retainers 22. After the coring operation is completed, it is a simple matter to disconnect the core tube .20 with a core therein from the plug 2% by unthreading the tube 20 from the plug 24.

I claim as my invention:

1. A reciprocating core drill comprising a hollow drill body having longitudinally extending slots therein, a hollow cutter head mounted on the lower end of said body, a core receiving tube mounted in said body to reciprocate therein, a circular cutter on the lower end of said tube, a plug on the upper end of said tube, a pin on said plug extending into the slot in said body, a stud on the upper end of said plug, a washer movably mounted on said stud, a coiled spring on said stud between said plug and washer, and a shoulder on said body formed at the upper end of the central opening therein arranged to engage said washer.

2. A reciprocating core drill comprising a hollow drill body having longitudinal slots therein, a hollow cutter head on the lower end of said body, a core receiving tube in said body, a circular cutter on the lower end of said tube, a pin mounted on the upper end ol said tube extending into said slots, resilient drivin means on the upper end of said tube, and means on said body for engaging said resilient means.

3. A reciprocating coredrill comprising a drill body, a cutter head mounted on the lower end of said body, a core receiving tube reciprocably mounted in said body to move longitudinally therein, a circular cutter on the lower end of said tube. means for preventing relative rotation between said body and said tube, and means for preventing direct impact between said body and tube com prising resilient means on said tube adapted to be engaged by said body upon downward movement of the body.

4. A reciprocating core drill comprising a hollow drill body having longitudinal slots therein, a hollow cutter head on the lower end of said body, a core receiving tube in said body. a circular cutter on the lower end of said tube, a pin mounted on the upper end of said tube extending into said slots, and means for preventing direct impact between said tube and body consisting of a shoulder formed in said drill body and resilient means mounted on the upper end of said tube adapted to be engaged by said shoulder upon down 'ard movement of said body.

A reciprocating core drill comprising a hollow drill body having longitudinal slots therein. a hollow cutter head on the lower end of said body, a core receiving tube in said body, a circular cutter on the lower end of said tube, a pin mounted on the upper end of said tube extending into said slots, a shoulder formed in said drill body and resilient means mounted on the upper end of said tube adapted to be engaged by said shoulder, said resilient means consisting of a stud, a coiled spring on said stud, a washer movable on said stud and means for limiting the movement of said washer on said stud.

6. In a reciprocating core drill, a drill body having longitudinal slots extending therethrough internu-diate its ends, a cutting member mounted on the lower end of said body, a core tube mounted in said body to reciprocate therein having openings in its upper end, a plug in the upper end of said tube, a cutter on the lower end of said tube, means for limiting the relative longitudinal and rotative movement. between said drill body and core tube, comprising a pin mounted in said plug having its ends extending into said slots and means for preventing direct impact between said body and said tube comprising yielding means mounted on said tube.

In testimony whereof. I have hereunto set my hand at Houston, Texas, this 19th day of April, 1926.

CARL J. HILLMAN. 

